This application is a national stage of International Application PCT/EP2009/053866, filed Apr. 1, 2009 and claims benefit of and priority to German Patent Application Nos. 20 2008 005 073.1 filed Apr. 11, 2008, and 20 2008 013 086.7, filed Oct. 1, 2008, the content of which Applications are incorporated by reference herein.
The present disclosure relates to a hot runner nozzle for lateral injection of plastic components. The nozzle includes a multi-part nozzle body having one or more tip elements which protrude outwardly over a circumferential area of the nozzle body.
WO 99/37 461 A1, US 2002/0098262 and EP 0186 413 A2 are representative of the technological background.
It is often advantageous in the field of injection molding for plastic to perform injection for plastic parts laterally, that is perpendicularly or obliquely in relation to the demolding direction. For this purpose, so-called hot runner nozzles for lateral injection are used, which are also known as lateral injection nozzles and which comprise a nozzle body and tip elements. In order to achieve good temperature control for the melt up to the surface of the article, the nozzle tips or tip elements must be guided up to the surface of the article.
It is further known to divide the mold components, or the die components, which enclose the nozzle body, so that the nozzle tips or the nozzle body can be mounted in the case of multi-cavity arrangements. Such a state of the art is shown in DE 100 08 471 A1. The division is disadvantageous because a complex construction of the die needs to ensure the necessary retaining forces in order to prevent leakages.
That is why constructions of lateral injection nozzles with tip elements appear to be advantageous which allow using non-divisible inserts. This can occur for example with adjustable tip elements, as proposed in DE 197 42 099 A1, or with the help of subsequent mounting of the tips in an integral nozzle body once the nozzle body has been mounted (see EP 1524091A2 and DE 103 45 578 A1, for example). In the case of the tip elements held in tight fit, the fit clearances are so tightly held after some time of use by the combusted plastic that destruction-free dismounting is often not possible.
The disadvantages of an adjusting mechanism are the filigree components which are partly wetted with the melt and after prolonged use no longer allow reliable adjustment or dismounting of the tips. The adjusting devices often do not permit any high force/pressure loads because they do not offer sufficient pressure surface due to the limited overall space.
The tip elements that can be mounted in the integral nozzle body on the other hand must be arranged to be very small in order to remain mountable. Moreover, the mounting/dismounting in known systems is exceptionally difficult and can often only be achieved with the destruction of the tips after prolonged use.
It is known from the generic EP 0 447 573 A1 and the priority-establishing DE 90 03 574 to arrange the nozzle body not in an integral manner but in a divided way, so that this difficulty is reduced. A holding ring is placed on a kind of base part (see FIG. 1 of EP 0 447 573 A1), on the axial side of which guide tips are held with a clamping ring. The mounting and dismounting of the tip elements is still not simple enough. Moreover, the melt flow is also not guided in a leakage-free manner from the melt entrance into the nozzle body up to the gate on the article, because the melt can also exit axially from the base part and flow about the guide tips. Considerable difficulties can occur during the dismounting of the tip elements by the ambient solidified plastic compound. The solidified plastic compound needs to be removed at first in a laborious fashion. Alternatively, the hot nozzle can be dismounted with the still doughy plastic.
The present disclosure is, therefore, based on further developing this generic state of the art, based on the concept of a divided nozzle body, in such a way that it is possible to house even relatively large tip elements in the nozzle body in a simple manner and to mount them and dismount them again after longer use in an easy manner.
The present disclosure thus relates to a hot runner nozzle for lateral injection of plastic components. The nozzle includes a multi-part nozzle body including at least one tip element which protrudes outwardly over a circumferential area of the nozzle body. The multi-part nozzle body further includes a nozzle body clamping disk section and a nozzle body base section having an axial side that has at least one recess arranged on the axial side to accommodate the at least one tip element which is pressed with the nozzle body clamping disk section against the axial side of the nozzle body base section.
The present disclosure provides for a hot runner nozzle which is arranged in such a way that the tips can be inserted easily in a multi-part nozzle body which previously has been built into a die. The chosen arrangement allows arranging the tip elements with a relatively large overall size.
US 2005/0196486 also shows an integral nozzle body with a projection integrally formed thereon. FIG. 2 of the present disclosure has a different hatching than the remaining nozzle body for illustration purposes.
In accordance with the present disclosure, the at least one tip of a tip element easily reaches the surface of the article to be injected. And, after a complete mounting of all components, the melt flow is guided in a leakage-free manner from the melt entrance to the nozzle body up to the gating on the article.
Relatively large retaining forces can be realized by the arrangement, according to the present disclosure, of the nozzle body, so that high tightness can be achieved.
After the mounting of the tip inserts, the sealing sleeves rest on the wall of the die insert, according to an embodiment of the present disclosure. Or, they are spaced to such an extent that, after reaching the operating temperature, there is sufficient surface pressing between the sealing sleeve and the wall of the die insert by thermal expansion of the overall nozzle.
Other aspects of the present disclosure will become apparent from the following descriptions when considered in conjunction with the accompanying drawings.